0\ \ \ \ \ \ \ \ \ not\ \ \ \ \ b>=0\\ \\ \sqrt[3]{\frac{343x^{6}}{125y^{9}}}=\frac{7x^{2}}{5y^{3}} \\ \\ \sqrt[4]{\frac{9c^{6}}{4d^{4}}}=\frac{\sqrt{3}c\sqrt{c}}{\sqrt{2}d} \\" alt="\sqrt[]{\frac{81a^{4}}{b^{4}}}=\frac{9a^{2}}{b} \\ b>0\ \ \ \ \ \ \ \ \ not\ \ \ \ \ b>=0\\ \\ \sqrt[3]{\frac{343x^{6}}{125y^{9}}}=\frac{7x^{2}}{5y^{3}} \\ \\ \sqrt[4]{\frac{9c^{6}}{4d^{4}}}=\frac{\sqrt{3}c\sqrt{c}}{\sqrt{2}d} \\" align="absmiddle" class="latex-formula">